Playa/hosts/Volcanic.AgenticCore.Telegram/Scheduling/CalendarScriptEnvironment.cs

using System.Globalization;
using Volcanic.AgenticCore.Extensions.GoogleCalendar;
using Volcanic.AgenticCore.Extensions.Scheduler;
using Volcanic.AgenticCore.Telegram.Chats;

namespace Volcanic.AgenticCore.Telegram.Scheduling;

/// <summary>
/// Gives a chat's watcher scripts <c>GOOGLE_ACCESS_TOKEN</c>: an access token for that chat's calendar, valid for the
/// run's timeout plus a minute (as far as Google's one-hour lifetime allows). The bot refreshes it; the refresh token
/// and the client secret never reach the script. A chat without a connected calendar gets nothing.
/// Takes <see cref="TelegramOptions"/>, not <see cref="ChatRegistry"/>: the registry depends on the scheduler, which
/// depends on this.
/// </summary>
public sealed class CalendarScriptEnvironment(TelegramOptions options, GoogleCalendarOptions calendar) : IScriptEnvironment
{
    public const string AccessTokenVariable = "GOOGLE_ACCESS_TOKEN";
    private static readonly TimeSpan Margin = TimeSpan.FromMinutes(1);
    private static readonly IReadOnlyDictionary<string, string> None = new Dictionary<string, string>();

    public async Task<IReadOnlyDictionary<string, string>> ForRunAsync(string target, TimeSpan timeout, CancellationToken cancellationToken)
    {
        if (!long.TryParse(target, NumberStyles.AllowLeadingSign, CultureInfo.InvariantCulture, out var chatId)) return None;
        var token = await (calendar.Connections ?? GoogleCalendarConnections.Shared)
            .TryGetAccessTokenAsync(calendar, ChatRegistry.ScopeFor(chatId), ChatRegistry.WorkspaceFor(options, chatId), timeout + Margin, cancellationToken)
            .ConfigureAwait(false);
        return token is null ? None : new Dictionary<string, string> { [AccessTokenVariable] = token };
    }
}